CTAB adsorption onto dolomite in the presence of ionic liquid and deep eutectic solvent: Experimental and theoretical studies

Abstract

Surfactant adsorption onto reservoir rock surfaces would undesirably influence its functionality from standpoint of enhanced oil recovery (EOR). This study investigates the performance of an imidazolium-based ionic liquid (IL) and a choline chloride-based deep eutectic solvent (DES) as additives to inhibit cetyltrimethylammonium bromide (CTAB) adsorption onto dolomite rock surface from experimental and theoretical perspectives. In the experimental part, static adsorption tests were conducted using UV–Vis spectrophotometer to find the adsorption density of the chemicals in both single (e.g. only CTAB) and combination modes (CTAB-IL and CTAB-DES). In addition, Langmuir and Freundlich isotherms were used to fit the experimental data and also to discern the adsorption patterns. In the theoretical part, interaction energies were determined using the XDLVO theory. The experimental results revealed lower adsorption of IL and DES in comparison with CTAB. Moreover, the addition of IL and DES, as potential adsorption inhibitors, effectively reduced CTAB adsorption where almost 73% reduction was observed when 1000 ppm of the IL was added to 2000 ppm of CTAB in seawater. From theoretical investigation, it was found that among different interaction energies, Lewis acid-base interaction was primarily dominant. The consistency between the experimental and theoretical results was further confirmed when the work of adhesion was calculated and compared for different chemicals investigated in this study.